How to Test The Alternator Field with a Screwdriver [Simple Guide]

How to Test The Alternator Field with a Screwdriver

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Car alternators are one of the most essential elements of a car. They must be constantly maintained and checked (even if they do not require much maintenance) to maintain their optimum performance as they supply the battery with a continuous flow of electricity.

So how do we test the alternator’s field using a screwdriver, what is an alternator, and what are the signs that your alternator is starting to become weaker or needs some repairs? Throughout this article, we will try to answer these questions to give you an overall better understanding.



It is vital that you maintain your safety as your safety is, of course, the top priority, and since we will be working with screwdrivers and electricity. The best option will be to wear insulating gloves to protect your hands from anything that might occur.

What Is an Alternator

Alternators are generators that operate on electricity, and as we said before, they are one of the most important elements that make any car run. Alternators work after a car’s engine starts, and they start to charge the car’s battery while also supplying electricity to any other electrical system. Alternators are located near the engine as they are bolted to it and are driven by a drive belt.

As we said before, alternators do not need much maintenance as they are very durable and can last for many years. However, if at any point your alternator fails or malfunctions, your car will stop after a short amount of time. As it will run on the electricity stored in the battery, which will eventually run out due to the alternator not supplying it with power anymore.

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How to Know if Your Alternator is Malfunctioning

The easiest way of knowing that your alternator is not working or malfunctioning is that a battery shaped light will turn on in your dashboard, and it will not turn off. Usually, the light starts when you turn your car, and then it shuts down, however, if this battery icon does not shut down and keeps lighting, this means that there might be a problem with your alternator.

A second method of knowing concerns your car’s headlights and dash lights. If the dash lights and the headlights are dim when they are idle but become brighter when you rev your engine. This means that not only your alternator might be malfunctioning, but also it might mean that there is a problem with your battery as well.

Also, if you hear any sound or noise coming from your alternator like a buzzing sound, this definitely means that there is a problem with your alternator.



Now that we have known everything that we need to know about alternators. We have reached the step that we have all been waiting for. To test for the alternator’s currently using a screwdriver, you need to:

1. Insert Your Key into the Ignition

This is the first step towards testing your alternator’s current. All you have to do is to put your keys into the ignition and turn the key so that it reaches ignition without starting your engine.

2. Open Your Hood

It goes without saying that you need to open your hood in order to reach the alternator, as it is located near the engine. So open your hood and do not forget to secure the hood using the latch.

3. Bring the Screwdriver Near the Alternator

This is the most important step as, first of all, you need to turn your key till it reaches the on position without starting your car. You will now need to bring your screwdriver using the metal tip close to the alternator. Bring the screwdriver’s metal tip close to the nut located on the alternator’s pulley. 

If you observe high magnetism and see that your screwdriver is being pulled towards the alternator, then it is working perfectly. However, if this doesn’t happen, then there is something wrong with your alternator, and you need to get it checked as soon as you can.


How to Protect Your Alternator

Protecting your alternator is all about protecting your engine. This means that if your engine is safe, then your alternator will definitely be safe as they are so close to each other. Therefore, if your engine’s protective undercover is damaged or missing for any reason, you need to replace it as soon as possible to prevent any water or splashes from the road from reaching your alternator or engine.

Moreover, whenever you decide to wash the engine compartment, the alternator must be covered so it can be protected from water and shampoo. Also, you need to be wary of any oil leaks that may occur in your car, as they might end up damaging your alternator.


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Final Thoughts

Finally, it is safe to say that knowing how to test your alternator using a screwdriver is an indispensable skill that always comes in handy. It will definitely help you in identifying a problem before it occurs.

It is also a straightforward process, as all you have to do is to put your car key in without turning it on, open your car’s hood and secure it, then turn your key towards ignition without turning your engine on and finally bring your screwdriver close to your alternator and wait for the magnetism to take its place.